Carbapenem Resistance is Associated with Biofilm formation in Clinical isolates of Klebsiella pneumoniae

Vollständiger Abstract

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Carbapenem-resistant Klebsiella pneumoniae (CRKP) and biofilm-producing nosocomial pathogenic bacteria may complicate treatment and infection control. The relationship between carbapenem resistance and biofilm formation remains poorly characterized. Susceptibility to imipenem, doripenem, ertapenem, amikacin, and levofloxacin was assessed using the Kirby-Bauer disk diffusion assay and CLSI M100 breakpoints for ninety-five non-duplicate clinical isolates of K. pneumoniae. The crystal-violet microtiter assay, which measured the optical density at 570 nm and was categorised based on Stepanovic criteria, was used to measure the ability of the isolates to produce biofilm in vitro. Based on the isolates' carbapenem resistance results, the isolates were classified as carbapenem-resistant (CR), carbapenem-intermediate (CIN), and carbapenem-susceptible (CS). The susceptibility rates were 74.0%, 68.8%, 63.5%, 46.0%, 73.1%, and 68.4% for imipenem, doripenem, meropenem, ertapenem, amikacin, and levofloxacin, respectively. The results showed that 43.2% (41/95) were resistant to a carbapenem antibiotic, while 16.8% (16/95) were multidrug-resistant. When the biofilm product was assessed, 35.4% of the isolates were moderate biofilm producers, 43.8% were strong biofilm producers, and 20.8% were weak biofilm producers. The OD570 of biofilm formation was significantly higher in CR isolates than in CS isolates (0.59 vs. 0.424; Mann-Whitney U=976.5, p= 0.03). Resistance to carbapenems was significantly correlated with biofilm formation (Spearman ρ = 0.224, p = 0.028). Isolates with strong biofilm formation were more frequent in CR-KP than in CR-KP (53.7% vs. 36.4%), but the distribution was not significant (χ² =3.16, p =0.206). It can be concluded that carbapenem resistance was common and associated with a moderate increase in biofilm production. This study recommends continued surveillance, and large genotypic studies are warranted.